Now What?
 

OK I just got my props back from being lab finished and got no increase in rpm's or speed. I don't know where to turn next. The boat is a 1999 eliminator daytona cat twin HP500's carb. Bravo1 30 pitch 4 blades turning in. I tried them turning out and were a little slower. The boat runs to 94 mph on gps and turning 5000 rpms. This is exactly what it ran with the props brand new out of the box. I called eliminator boats and they told me they use John York from York propeller for all of their race boats and said he is the best. I called him & he felt he could get 200 more rpms easily maybe get 300. Well after the labing I got the exact same results. Other guys on this site with same rig claim 97+ at 5300 rpms. The former owner claims that the boat ran 100 at 5350 rpms? The boat has 300 hours on the motors and the are both spinning the same rpms so it leads me to think that one is not down on power and I would find it hard to believe they both would equally be down on power due to some sort of failure.Could it be timing? The boat was purchased in California and the fuel out there is different I think? I am running on a lake in NJ at 900 feet above sea level. Could this be the reason. The people I bought the boat from never ran it in slat water so I know that is not reason. I am going to run it at the jersey shore aug 14th for a week and I will see if see level makes that big of a difference. I am so frustrated and don't know were to look. Any help would be appreciated. Especially from the eliminator dyatona owners.

Re: Now What?
 

Have you had the motors scanned for codes? I know it is not likely that both would have a problem at the same time, but who knows.

Re: Now What?
 

I have not had that done. The engines are not efi's they are carbs and I think the computer does very little on these motors.

Re: Now What?
 

You are right, it was just a thought. Sorry.

Re: Now What?
 

At 300 hours I would think the valve springs could be getting tired. They can be a great rev limiter. Do you know if they have ever been changed?

Re: Now What?
 

I do not think they have ever been changed. Is this a big job changing the valve springs? Do the heads have the come off? If so I will live with it until I need to rebuild the motors. I just find it odd that previous owners only put about 50 hours on the boat and they were getting more revs and mph. Do valve springs slowly weaken? I know they were prone to breaking on these motors but they were checked out by Teague custom marine and were not broken.

Re: Now What?
 

Not that I think that it's urgent, but valve springs and lifters are regular maintanence items in an engine like yours. After the mess I had when a roller lifter broke in one of my engines, I will never neglect them again. Over the winter I would get a valve job and replace lifters and valve springs.

Re: Now What?
 

200 or 300 rpms... I've seen that much difference between a nice mild day and a hot humid day. 900 feet altitude will make a difference too. Where did the last guy get his 100 mph? That too will make a difference :rolleyes:

Re: Now What?
 

Your valve spring DEFINATELY need changed. Do a search on Valve Springs and HP500 here on OSO. This has been discussed about 1200 times.

Re: Now What?
 

The last owners ran the boat in lake havasu and lakes around Los Angeles. I do not know the altitude out there. When I flew out to California to see the boat the lake the owner took me to seemed like it was up in the mountains but I do not know the altitude. Does it seem odd to get no difference in any thing like RPMS or Speed from labing props. I would of thought something would change. The boat feels as if nothing was done. Also do you guys think Hydromotive 4 blade labed 29 pitch would run better the the bravo 4 blades? Any suggestion's are greatly appreciated.

Re: Now What?
 

In situations like this, I like to slow down and back up a bit. You made a change to the props and saw no results. If you make the assumption that the boat ran 100mph with the stock props that you had reworked, then maybe the mods were not effective. Although that seems unlikely, York has a good reputation. So lets look at the health of the motors, well both of them, not likely that they are both sour. So then weather, altitude, motor health, etc. How about air to the motors, or fuel psi. Did you make any changes before you ran the boat? Did you ever see the speed that you are shooting for? I would say that you may need springs, motor freshen, etc. But that shouldnt drop 300rpms on both motors. I would think it is something common to both motors or their systems. Is there any exhaust leaks in the motor compartment, that could hurt performance. I would do a compression and leak down test to see if the motor is up to par and balance. I would check timing on both motors, make sure no changes were made somewhere along the way.
My point is, take it slow and easy. You are running faster than a lot of people, so relax, at least you are running. Look at all the variables, investigate and eliminate them one at a time. Logic prevails when you troubleshoot methodically..

I dont have the answers, just some thought to help you find out what is going on. I know a lot of people are working on their boats and they done even run, so it is all relative.

Good luck
Dick

Re: Now What?
 

You may get to 97 going up 300 rpm's but i would doubt on another 50 rpm's you will get to 100? Did this boat spend anytime in the salt water? That would get the numbers up to 100 just based on the salt to fresh water difference, altitude is probably playing some roll but sounds like you have some drag if the motors are sound.

Re: Now What?
 

Thanks guys. Just to make things clear. I never saw 100mph. The people I boat the boat from and Bob Teague told me face to face that the boat ran a solid 100mph at 5300 rpm. Now when I got the boat back in May the best it ran was 92mph on gps. So I called Bob Teague asking for any Ideas. He had said that the guy I bought the boat from had dinged up the props and I should buy a new set of Bravo 30p 4 blades. He said that is what this boat likes the best. Bob is renowned in the high performance boating world as one of the most knowledgeable guys there are so I figure listen to him. I bought the props and after running it with the new props I got a best speed on gps of 95 but still turning only 5000-5050 rpms. So I called eliminator and asked there service manager and he said he would have the props labed by John york. So I sent the new props to John York who said I should get at least 200 rpm more and maybe 300-400. So after I got the props back from York I ran the boat again and there was zero improvement. So that said It leads me to believe the motors just cant turn 5300 rpms and that I think based on everyone saying that the valve springs should be replaced with 315 hours on the motors it makes sense to me that that is the problem. Does any one know how much time it typically take to do 2 motors in a 28 Daytona? I am not going to attempt this myself. I wonder what I should be paying in labor? Any help would be appreciated.

Re: Now What?
 

Dave, I still would not give up on the props yet, I think there is some more work that could be done there that will net you what your looking for, I just had a pair of Bravo 1 30's done by Houston Propeller and Darin was able to get me 300 more rpm's and a "Solid" 3 mph on gps for my Formula 312, they were labbed blueprinted and i think he trimmed the diameter some so i could spin them up, i went from turning 4700 rpm's to 5000 rpm's going from no trim to 5 on mechanical indicators and still holding, so if they are done right you should have gained, i dont think just labbing would have done it for you, Jeff

Re: Now What?
 

I agree with Mopower. Altitude, temperature, and humidity make a huge difference. Your only at 900', but what is the humidity between you and the 100mph setting?

Re: Now What?
 

Dave,
Since you never saw the boat do 100 mph , you don't know the exact conditions this happened under.
Low humidity , 65*, that will get you a little more. Now here's the real kicker...
I know you said it was never used in salt water but you can still operate in tidal waters as I do and not touch salt. That extra 2 or 3 mph could have been running "with" the tide , which will be added too you speed.
When I buy something , I believe what I see , not what I hear.
I hate to be so negative but I just hope you're not chasing a dream(or sales pitch). You know what they say "A boats always 5 mph faster on the trailer"

Good luck in any case. Keep us posted :)